LCARS & Finger Grease?

So what does LCARS do with finger grease? Is there self-cleaning tech at play, or does the janitor clean the screens during the night shift? I can't use my iPad without turning it into a deep-fryer. Same goes for other bodily fluids.

I'd imagine they have a more advanced version of the oil-repelling coating on modern smart-phone glass that lets you easily wipe off fingerprints with any dry cloth. On Star Trek, fingerprints probably just slide off glass, or the oil is repelled so much it doesn't transfer from the skin.

There is an episode of TNG where Data slams his hands into his navigation touchscreen and leaves a huge smear of grease behind. It's only really noticeable now it's been remastered. Perhaps he had an oil leak?

Even today, some devices come with an oleophobic coating. The problem is it wears off very quickly. It is easy to imagine a perfected coating, or a material which is naturally oleophobic by the 24th century.

1) Surely the 24th century would have come up with a means to remove stains from flat surfaces, and others. There's both a demand and no doubt an abundance of means.
2) Indeed, we hear this has happened: Riker says the ship cleans itself.
3) And we see this happen, and hints at how it happens: stains of all sort appear, but then change shape, and ultimately disappear.

Trained bacteria sound like a realistic solution from today's vantage point. But 24th century is way beyond realism and entitled to other solutions - just like the real 20th century was way beyond realism from preceding vantage points, and entitled to solving ages-old problems of communications, computation, commuting or combat with all sorts of apparent dark magic.

T0S & the early T0S movie bridge buttons make more sense to me, because it's like ... you can't always look at the console, whilst you're typing shite. With LCARS everything you type seems the same, there's no real way to differentiate one "key" from another. Though, I must confess to never having given any thought to finger-grease, before ...